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Discussion Starter #1
Before:


While I think I'm going to miss the shiny zinc finish of my 750VS, I have high hopes for the 650DP I installed today. I've been toying with it for the last week getting its baseline state setup as good as I could.

It got new fuel bowl & metering plate gaskets (changed the old cellulose ones to the new blue ones), an electric choke upgrade, new jets (71/74 as a start), new squirters (.035), and the transfer slot set to the baseline .020 setting. I didn't swap pump cams because it already had pink cams installed and I figured they were a good starting point. I even found some nice braided vacuum line to play with. :rolleyes:

After:


The new setup is almost ready to fire except that I need a new fuel line adapter (-6AN to NPT) for the dual feed line inlet. I'm not 100% sure I like the fuel inlet kit I bought. It was a cheapo Spectre unit, but I was hoping to get this thing fired today and failed miserably due to parts inavailability based on the wrong assumption that a 4150 used the same inlets as a 4160. Wrongo. :eek: The Spectre kit is a quick-fix. If it doesn't leak like crazy, I may keep it.

I'd have gotten more done today but I cleaned up the garage first. That felt really good to get done first. Now if I could only talk myself into better plug wire routing (via homemade MSD wires) and wrapped engine bay wiring. :shh: Getting the Caltracs installed properly and setup comes first though. Today's playing was time filler until I get all of my parts & Calvert's parts to cooperate.

Have I typed enough yet??
 

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FWIW like the original Holley finish(an old school look) way more then that shinny finish.....looking good Brent:cool: :)
 

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Discussion Starter #3
NovatoriusWrecks said:
I'm not 100% sure I like the fuel inlet kit I bought. It was a cheapo Spectre unit, but I was hoping to get this thing fired today and failed miserably due to parts inavailability based on the wrong assumption that a 4150 used the same inlets as a 4160. Wrongo. :eek: The Spectre kit is a quick-fix. If it doesn't leak like crazy, I may keep it.
I figured that my unconscious brain knew better than my conscious one..... The dual feed inlet that I bought is complete crapola and leaked like a sieve even after repeated attempts at tightening up the hose clamps. It's going back to the store. :mad:

Anything worth doing is worth doing right, so I'm going to go visit the Aeroquip fittings store down by my work at lunchtime tomorrow. They're bound to have something workable. If not, there's always Summit.

The good news is that it fired right up after the fuel bowls filled. It idled at a rumpity 500rpm as I check for, and found, fuel leaks in the inlet tubing.

At least she's not completely dead. :D
 

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Congrats on getting it running. My advice on your carb; start with some -6 AN to fuel bowl adapters. Remove the Holley inverted flare adapers and measure the hole size. Aeroquip should have what you need.
 

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Discussion Starter #6
DOH! DOH! DOH!

It hit me after I got home from returning the Spectre kit. I'm such a bonehead for not realizing this earlier. The old Holley 3/8" hard line dual feed I had was only about 1" of being able to connect to both fuel bowl inlets.

I just happened to have some left over tube nuts from my 3/8" fuel line install, so I chopped the old hardline fitting in two, cut a bit of tubing off (coupler is long), added a tubing coupler for length, then 37* flared and fitted everything back together with tube nuts. Not a leak to be seen!



I'm rather proud of CHEAP innovation. It cost me nothing other than a few minutes digging through my parts stash. :D

Now all I have to do is set the idle mixture for max vacuum and I'm ready to run....I'll be ready to race once I get my Caltrac issue fixed. :rolleyes:

 

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I'm sure I am not seeing this corectly but is that braided line coming out of the primary metering block hooked up to the vaccum advance can on the distributor? If it is would that not be a ported vacuum source (seeing that it is above the throttle plates)....Would you not want to hook it up to an unported source (below the throttle plates) so you would get full manifold vaccum at idle? :confused:

http://www.stevesnovasite.com/forums/showthread.php?t=11689

Vacuum Advance 101 said:
Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it.

If you look at the centrifugal advance calibrations for these "ported spark, late-timed" engines, you'll see that instead of having 20 degrees of advance, they had up to 34 degrees of advance in the distributor, in order to get back to the 34-36 degrees "total timing" at high rpm wide-open throttle to get some of the performance back. The vacuum advance still worked at steady-state highway cruise (lean mixture = low emissions), but it was inoperative at idle, which caused all manner of problems - "ported vacuum" was strictly an early, pre-converter crude emissions strategy, and nothing more.
 

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Discussion Starter #8 (Edited)
69NovaSS said:
I'm sure I am not seeing this corectly but is that braided line coming out of the primary metering block hooked up to the vaccum advance can on the distributor? If it is would that not be a ported vacuum source (seening that it is above the throttle plates)....Would you not want to hook it up to an unported source (below the throttle plates) so you would get full manifold vaccum at idle? :confused:
Oh gawd NOOOOOOOOOOOOOOOOOOOOOOOO..... please don't start the vacuum advance wars in my thread. :rolleyes:

I have it hooked up there right now because I don't see another vacuum port on the carb handy at the moment. I might not be looking hard enough though.
 

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I believe it's up underneith the front inlet fitting on the very bottom of the carb.

Kev
 

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novaboy009 said:
I believe it's up underneith the front inlet fitting on the very bottom of the carb.

Kev
what he said...it should be on the very bottom of the carb on the aluminum part(base plate) I believe there should be a port there:)
 

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NovatoriusWrecks said:
Oh gawd NOOOOOOOOOOOOOOOOOOOOOOOO..... please don't start the vacuum advance wars in my thread. :rolleyes:

I have it hooked up there right now because I don't see another vacuum port on the carb handy at the moment. I might not be looking hard enough though.
sorry man not trying to go off on a tangent in your thread but the car will work better with it hooked up correctly....and if it works better you will likely have better 1/4 mile times then too;) :)
 

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Discussion Starter #12
69NovaSS said:
sorry man not trying to go off on a tangent in your thread but the car will work better with it hooked up correctly....and if it works better you will likely have better 1/4 mile times then too;) :)
Honestly, I didn't even think about that being a ported vacuum port. I thought "Ooooh, vacuum port, and plugged the hose onto it".

I appreciate the heads up. I may have to consider putting a tee in my trans modulator vacuum line because I really don't remember seeing a manifold vacuum port on the baseplate of this carb. :awkward:
 

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Looks good - It will be interesting to see how much it affects your time.

Something I recently learned that may help out here in the future if you think you may be changing jets alot.

If you replaced the had line between the two bowls with 3/8 rubber fuel / you can pull the front bowl off to change jets with out taking off any of the gas lines.

You should be able to get away with double clamping the rubber hose on both ends to prevent leaking.
 

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Discussion Starter #14
NEVER FINISHED64 said:
Looks good - It will be interesting to see how much it affects your time.

Something I recently learned that may help out here in the future if you think you may be changing jets alot.

If you replaced the had line between the two bowls with 3/8 rubber fuel / you can pull the front bowl off to change jets with out taking off any of the gas lines.

You should be able to get away with double clamping the rubber hose on both ends to prevent leaking.
Interesting suggestion, thanks for the idea. I guess that could be done with braided tube also. I'm not gonna constantly juggle jets though. I won't see the track often enough to make it worth the effort. It's gonna go to the track every so often just to see what it's capable of and for fun, nothing more.
 

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NovatoriusWrecks said:
It's gonna go to the track every so often just to see what it's capable of and for fun, nothing more.
That's what I said, LOL, and now look what happened :eek: ;)
 

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NovatoriusWrecks said:
Yeah, but you little Amish boys are going to get addicted to the first drug you try. Yours just happened to be SPEED! :p
So THAT explains it!
 

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Discussion Starter #19
NovatoriusWrecks said:
Honestly, I didn't even think about that being a ported vacuum port. I thought "Ooooh, vacuum port, and plugged the hose onto it".

I appreciate the heads up. I may have to consider putting a tee in my trans modulator vacuum line because I really don't remember seeing a manifold vacuum port on the baseplate of this carb. :awkward:
All I can say in my defense now is......OOPS! :eek:



I'm glad I have you guys to sanity check my work. :beer:
 

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Discussion Starter #20
Hehe.....it gained 1000RPM at idle just hooking up the vacuum advance correctly. I've changed nothing else...:rolleyes: I definitely have some retuning to do.
 
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